1. Field of the Invention
The present invention relates to a light source device having a plurality of light emitting elements arranged in a linear configuration, and arranged on the side surface of a light guiding plate for making a planar light source device. Also, the present invention relates to the planar light source device.
2. Description of the Related Art
There is a planar light emission light source having a light guiding plate and a linear light source device arranged on the side surface of the light guiding plate (for example, see Patent Reference 1) as the backlight light source of the liquid crystal display panel for use in cell phones or digital cameras, etc.
The linear light source device includes a printed circuit board having a slender rectangular-shaped wiring pattern formed thereon, light emitting elements arranged in plurality separated from each other along the longitudinal direction of the printed circuit board on the printed circuit board and connected with the wiring pattern of the printed circuit board, reflectors arranged on one side and the other side in the longitudinal direction of the various light emitting elements, respectively, and having a slope surface, and a sealing resin for sealing various light emitting elements.
For the linear light source device, when thermosetting is carried out for the sealing resin, the linear light source device wraps convex downward (in the direction to the surface on the side opposite to the surface of the printed circuit board where the light emitting elements are assembled). As a result, its adhesive property on the light guiding plate degrades, and the light incidence efficiency to the light guiding plate decreases.
According to Patent Reference 2, the reflector arranged for a light emitting element and the reflector arranged for the adjacent light emitting element are not arranged continuously in order to prevent warp of the linear light source device. They are separated from each other by arranging a groove instead. The groove can relax the stress generated due to contradiction of the sealing resin, and it can prevent warp.
In addition, for the conventional linear light source device, a ribbon-shaped flexible substrate is attached for connecting the linear light source device with a power supply (Patent Reference 3).
Patent Reference 1: JP-A-2004-235139
Patent Reference 2: JP-A-2006-120691
Patent Reference 3: JP-A-2009-32479
However, the method described in Patent Reference 2 has insufficient effect in preventing warp. It has low close contact property with the warped light guiding plate, low light incidence efficiency to the light guiding plate, and low luminance of the backlight light source.
As can be seen in Patent Reference 3, when a flexible substrate is used to connect with the power supply, and the planar light source device is configured from the linear light source device and a light guiding plate, the planar light source device becomes bulky because there is the flexible substrate portion, which is undesirable.